Use the following steps to get your Trimble Positions software upgraded to the new version:

1.       Make sure all current project data has been checked in, post-processed or backed-up if necessary before upgrading.

2.      Go into ArcMap, and go to Customize>Extensions.  Turn off the Trimble Positions extension.

3.      Go into Customize>Add-ins.  Find the Trimble Positions Add-in and delete.

4.      Close out of any ArcGIS or Trimble-related program.

5.      Uninstall Trimble Positions Desktop add-in using the control panel.

6.      On the computer, open Windows Explorer.  Go to C:\Users\your profile.

7.       In Windows Explorer, at the top path name, after your name, Paste AppData\Local\ESRI\Desktop10.4\AssemblyCache in the address bar.  The path should look like this (with your name in place of my name) - C:\Users\alison\AppData\Local\ESRI\Desktop10.2\AssemblyCache. 

8.     Delete the folder named “{53B8FB5F-6061-4667-84B8-ADE5C76D6BE3}” if present.

9.      Open ArcMap. 

10.   Close ArcMap.

11.    Download the latest Trimble Positions Desktop add-in

12.   Double-click the exe to install

13.    Activate the software using the Trimble Positions License Administrator.

14.    Once installed and activated, launch the Desktop Configuration tool from Start>Programs>Trimble>Trimble Positions Tools>Desktop Configuration

15.   Click “Test current configuration”

16.   Click yes if prompted to upgrade the schema

17.   Open ArcMap and go to Customize>Add-ins and ensure that the Trimble Positions add-in shows the proper version.  If it is not listed here, follow the directions in the blog post to get the add-in recognized by ArcMap: http://positionsblog.trimble.com/?p=361

18.  When you have the proper add-in showing in the Add-ins window, then you can go to Customize>Extensions and check on the Trimble Positions extension and continue working.